Musical instrument



July 21, 1936. v. A. PFEIL MUSICAL INSTRUMENT Filed April 28, 1953 2Sheets-Sheet 1 E l"; W

III] [I]! Patented July 21, 1936 UNITED STATES PATENT OFFICE MUSICALINSTRUMENT Victor A. Pfeil, Orange, N. .L. assimito Creszentia A. Pfeil,West Orange, N. J.

This invention relates to stringed instruments and it has particularrelation to a stringed musical instrument combined with transforming andamplifying mechanism installed in conjunction therewith.

The invention contemplates the provision of a stringed instrumentsimulating any well known type which is played manually and is designedfor directly producing a pulsating electric current for transformationand amplification into sound energy in the form of musical notes of theinstrument at a remote point.

In one embodiment of the invention a special construction of musicalinstrument is provided and in which a stick of wood, or other suitablematerial, is employed for mounting a conventional finger board, togetherwith a special bridge construction for receiving strings stretchedthereover. vibratory movement with respect to ;the stick in order thatit may operate and cooperate with an electric system constructed toreproduce the sound corresponding to the vibrations of the strings andbridge. The invention includes special construction of bridges forstringed instruments diiIering materially in construction and method ofinstallation from conventional bridges of ordinary musicalinstruments.

In referring to means for producing a magnetic field, it is to beunderstood that electromagnetic devices are intended to include magnetoelectric devices. can be induced through an electric circuit in whichelectromagnetic means is incorporated for varying a magnetic fieldaccording to vibrations of an armature, or a permanent magnet and coilcan be used in which the field of the. magnet or winding of the coil isprovided with an armature vibrated by vibrations of the musicalinstrument string to create the desired electric pulsations.

In arranging the elements of the instrument embodying the invention, abridge and transforming device are mounted upon a suitable supportingportion of the instrument, and an armature composed of soft iron ismounted in conjunction with the bridge and transforming device in suchmanner that the vibrations of the strings of the instrument createdirect and proportionate vibrations in the armature which, in turn,develop a pulsating electric current in the transforming device whosewave form is analogous to that of the note or sound produced. Thepulsating current is amplified to any desired volume and quality andagain transformed into au- The bridge is mounted for oscillatory or Thatis, electrical energy Fig. 5 is a cross section similar to Fig. 3 illus-15 trating another form of bridge and electromagnet connection;

Fig. 6 is a side elevation of the structure shown in Fig. 5;

Fig. 7 is a cross section'similar to Fig. 3 and illustrating stillanother form of bridge and elec tro-magnet connection;

Fig. 8 is a cross section similar to Fig. 3 illustrating another form ofbridge and electro-magnet;

the plane indicated by the line IX-JX of Fig. 8; Fig. 10 is afragmentary plan of a combined tail piece and electrical transmittingdevice; and

Fig. 9 is a plan of the structure as viewed from Fig. 11 is alongitudinal section taken substantially along the line XI-XI of Fig.10.

Referring to Figs. 1, 2, and 3, a musical instrument I0 is providedsomewhat similar to an ordinary violin in that it includes a scroll I I,string securing and tensioning pegs i2, and a neck I3 upon which afinger board I! is mounted. In

this structure the entire body portion or res,-

onator box, usually included in a musical instrument of this generaltype, is omitted and a suitably turned and finished stick it of wood orinsulating material is substituted therefor. In fact, the stick i6 issubstantially a continuation of and is approximately the same size asthe neck. In order to facilitate the manipulation of the fingers alongthe finger board and to provide for proper resting of the instrumentbeneath a person's chin, a lateral hand rest I1 is rigidly mounted uponthe stick adjacent the neck. and a lateral chin rest I! is rigidlymounted upon the rear or inner end of the stick.

A conventional violin tail piece I! having a loop 20 fitting over abutton 22 at the end oi the stick supports the rear ends of the strings23 while the strings are connected for adjustment .upon the pegs I! atthe outer end of the neck.

While this description refers to the manner in which the instrument suchas the violin is assembled with respect to the strings, it is of coursepossible to apply the same principle of construction to various othertypes of stringed instruments.

The strings 23 are supported between the end of the finger board I5 andthe tail piece I! by means of a bridge 25 which constitutes a part of adevice 26 for transmitting vibrations of the strings into electricalenergy having the same vibration or wave characteristics as those of thestrings. Since the vibrations of the strings 23 are transmitted throughthe bridge 25, the latter constitutes a vibratory or oscillatory member.This bridge has its feet 21 supported upon opposite spaced portions ofan armature structure 2| in the form of a bar, end portions of which arecarried upon blocks of yieldable or resilient material 29, such asrubber or rubber compound, mounted axially upon the outer ends or poles30 of electro-magnets 32. The poles are rigidly secured upon outer endportions of the legs of a U- shaped permanent magnet 33, and suitableinsulating material rigidly carries the magnet 33 upon the stick. It isof course to be understood that only one of the magnets 32 may be used,or that one of them can be omitted, although a more perfectly balancedarrangement is provided by using two as shown in the drawing.

Suitable insulated electric conductors 35 connected to theelectro-magnet, lead to a transformer 31, and the secondary terminals ofthe transformer 31 are, in turn, connected to an electric amplifyingsystem 35 including well known devices such as electron tubes, audiotransformers, batteries, and a loud speaker, all of which arerepresented diagrammatically in Fig. 1. It is to be understood thatother well known constructions of amplifying systems can be incorporatedin conjunction with the instrument described above.

In the operation of the arrangement described, a musician plays theinstrument by fingering the strings and vibrating them by means of a bowor otherwise. These strings are thus vibrated transversely and thevibrations produced are transmitted to, and cause proportionatevibration of, the bridge. From the bridge the vibration is imparteddirectly to the armature 28, and accordingly, there is generated, bymeans of the magnetic held of the magnet, a pulsating electric currenthaving a wave form similar to the wave form of the note or soundproduced by vibrating the strings. This pulsating electric current isamplified through the electric transforming and amplifying system 31-",and is finally transformed into an audible note or sound which is a truereproduction of the note as originally set up by the vibration of thestrings '23. Since it is possible to vary the volume and tone of thevibration sounds from the strings, the quality of sounds emitted fromthe amplifying mechanism can be regulated so as to present musiccommensurate in tone quality with that produced by the Iinest musicalinstruments.

It has been observed that the quality and timbre of a note reproducedand amplified by means of an electric circuit depends to a certainextent upon the freedom of vibration of the body producing or emittingthe original note. According to this invention such freedom of vibrationis secured by means of the resilient supports 25 for the bridge. If thebridge were not so resiliently mounted, then the period of vibration ofthe armature would necessarily be reduced, and hence, the extent ofvibration of the armature itself would be so reduced.

It is known that the quality of music emitted by violin depends largelyupon the character and 5 age of the wood of which the resonator box iscomposed. New violins do not produce the better quality of music becausethe wood is not of proper character, but tends to set up higher harmonicvibrations which to the ear are inharmonious with the fundamental. Inthe kind of instrument described herein the resonator box is not used,thus preventing the development of undesirable harmonies. Thisinstrument produces only weak sounds resulting wholly from thevibrations of the strings while the music to be produced is transmittedto the amplifier in the form of vibration directly from the bridge andarmature. Thus, the amplifier produces or presents the music of theinstrument in the desired manner.

In the construction shown in Figs. 4 to 9, somewhat differentarrangements of elements are included for producing results like thosedescribed above, in that an instrument I0 is constructed 25 generally inthe same manner as the instrument HI of Fig. i, but the mounting andelements of the transmitting devices corresponding to the device 25 ofFig. l are different in arrangement and construction, and hence, thefeatures thereof are 30 designated by different reference characters.

According to Fig. 4, a bridge 39 is mounted upon suitable armaturestructure in the form of a yoke having depending legs 52 and a resilientpad or block 53 supports the yoke along 35 its intermediate portion uponthe stick IS. A permanent magnet 55 is formed with upwardly extendinglegs 56 in slightly spaced end to end relation to the legs 52 of theyoke. In this construction the permanent magnet is integral with thepole 56 of the electro-magnet. A bar 55 of insulating material, orhaving insulating material between magnet 55 and the stick I6, issecured upon the lower wall of a slot 59 formed transversely in thestick. In order to secure proper adjustment of the magnet a pair ofthumb screws 60 are screw threaded through opposite end portions oi thebar 58 and into opposite marginal portions of the magnet 55. Theoperation of this arrangement is substantially the same as thatdescribed above, although finer adjustment can be obtained bymanipulating the thumb screws 50. The connection of the insulatedelectric conductors 35 from the electro-magnet to the amplifying system3|38, is the same in both cases.

Referring to Figs. 5 and 6, a bridge 52 is provided with downwardlyextending legs 53 straddling the stick i5 and having a block ofresilient material 55 supporting the bridge along its lower portion uponthe upper surface of the stick. Each so leg 63 of the bridge is providedwith armature structure 65 rigidly secured thereto and projectinglengthwise of the stick in spaced relation thereto. As best shown inFig. 6, the structure 65 on each side of the stick is secured nearer one66 of its ends than the other to the bridge. If desirable, the bridgecan be considered a part of the armature structure.

A permanent magnet 51 of U-shape having one leg thereof formed into anelectro-magnet 55 is secured on each side of the stick l8, and the endportion of the armature structure 65 on each side of the stick isslightly spaced from adjacent ends of the magnet 61. Suitable securingdevices 69 of insulating material rigidly secure the magnets 15 to thestick. The vibrations of the bridge are transmitted directly through theresilient material 85 and transmitted from the armature structure to theelectro-magnet whence they are electrically conducted through theinsulated conductors 36 to the transforming and amplifying apparatus31-48. If desirable the stick may be formed in such manner as to providea raised support I0, or this member can be formed separately and securedto the stick I6. In this kind of arrangement separate transforming andamplifying apparatus is applicable for connection to each electro-magnet60.

In Fig. 7 a bridge 12 has its legs I3 secured directly to suitablearmature structure in the form of a bar 15 which has a depending arm I6disposed substantially at right angles thereto. A supporting plate 11incorporated in the stick I6 and having a central recess 18, is providedat its opposite ends with resilient blocks I9 which support oppositeends of the armature bar 15 thereon. It will be observed that thecontiguous ends of the bar and plate project outwardly beyond the edgesof the supporting stick I 8, and that the angular armature arm I6extends from the armature bar between the blocks I9, through the recessI8, and in spaced relation down the side of the stick. A permanentmagnet 80 of -U-shape is rigidly mounted and insulated, as indicated at82, upon the stick in a recess or cuta-way portion 83 formed therein.Electro-magnets 85 are built upon the legs 86 of the U-shaped magnets,and these legs are slightly spaced in parallel relation to the armaturearm Hi. The insulated conductors 36 are connected to the electro-magnets85 and to the transforming and amplifying system 3'I38 as describedabove.

Figs. 8 and 9 illustrate another form of the invention wherein a bridge88 is supported by its legs 08 upon opposite end portions of armaturestructure including a bar 90 that is carried by blocks of resilientmaterial 92 upon the opposite ends of a supporting plate 93. Contiguousends of the bar and plate extend laterally beyond the opposite sides ofthe stick I6 and the plate is secured upon the upper surface of thestick.

A recess 95 is formed centrally in the plate 83, and a rod or pin 96extends rigidly and downwardly from the central portion of the bar toprovide a link from the bar to a metallic inverted cup 91 ofsubstantially cylindrical form that has its upper end wall 98 securedrigidly to the lower end of the rod 96. A low impedance sound coil 99carried on the cup, has its convolutions spaced, and secured about theouter cylindrical cup wall. The rod 96 and cup 91 constitute portions ofthe armature structure. This cup is disposed over a cylindrical head orpole I of a permanent magnet I02 in such manner that the outer wall andend of the cylindrical head remain slightly spaced from the inside wallsof the cup. The magnet I 02 is U-shape in form and is partially embeddedin insulating material I03 secured in the stick I6 to maintain themagnet firmly fixed therein.

The end of the magnet I02 opposite the head I00 is provided with a rigidextension I 05 in plate form having a suitable connection I 06 to thebody portion of the magnet. This plate flares toward the head and isformed with an opening I01 through which the head I00 and cup 91 are sodisposed as to be slightly spaced from the wall of the opening. Theelectric conductors 36 are connected to the coil 99 and to thetransforming and amplifying system 3I-38 in such manner as totransmitand amplify the vibrations of the strings in the same manner asthat described with respect to Figs. 1 and 2.

Referring to Figs. and 11, an instrument I09 is substantially the samein general construction as that shown in Fig. 1, but in this case a bodyor stick I I0 is not provided with a bridge of the type previouslydescribed. On the other hand, strings III are stretched directly from atransverse portion I I2, which serves as a substitute for a bridge andis incorporated in a tail piece I I3, to a neck and pegs (not shown)like those shown in Figs. 1 and 2. In this form of the invention thetail piece H3 is composed of metal for the additional purpose of servingas an armature structure, and is supported intermediately upon aresilient block II5 carried upon a raised support H6 that is secured tothe stick IIO.

A permanent magnet III, U-shape in form, is partially embedded ininsulating material I I8 carried rigidly in a recess H9 in the stick.Legs I of the magnet extend upwardly to provide poles for anelectro-magnet I22. The ends of the legs I20 are spaced slightly fromthe lower surface of the armature tail piece adjacent one end of thelatter. The other end of the tail piece is provided with an adjustingpin I23 extending loosely therethrough and secured rigidly in the stickI I 0. A suitable nut I 25 screw threaded upon the upper end of the pinimpinges upon the upper surface of the tail piece and serves to adjustthe latter nearer or farther from the ends of the magnet legs I20. It isof course to be understood that the taut strings II2 always tend topivot the tail piece about the resilient block against the nut I25. TheWires 36 are connected to the electro-magnet I22 and to the transformingand amplifying system 31-38 in the same manner as that described withreference to the other figures. 1

Since the operation of the construction shown in Figs. 1, 2, and 3 hasbeen explained in detail it is apparent that the other somewhatanalogous structures disclosed in Figs. 4 to 11, inclusive, function insubstantially the same general man ner. However, it should be notedthat, in the arrangement shown in Figs. 8 and 9, including the lowimpedance sound coil, the physical vibrations transmitted from thebridge vibrate the cup, and that by using this method, in which arelatively few coils are employed, it is found that fidelity of tone isexceptionally satisfactory.

Although several forms of the invention have been shown and described indetail it will be apparent to those skilled in the art that theinvention is not so limited but that various changes may be made thereinwithout departing from the spirit of the invention or fromthe scope ofthe appended claims.

What is claimed is:

1. In a stringed instrument, a solid body of bar form, a plurality ofstrings tensioned across portions of the body, yieldable means carriedupon said body, a vibration transmitting device carried by the body ofthe instrument, said device including an oscillatory member supportingportions of the tensioned strings, an electro-magnetic mechanismincluding a pair of electro-magnets disposed adjacent said member andhaving poles to form magnetic fields, armature structure included insaid device and confined directly between said yieldable means and saidoscillatory member to restrict the armature to vibrations correspondingto those transmitted from said oscillatory member thereto, said armaturestructure having portions extending into both magnetic fields of thepoles, said armature structure being vibratory upon said yieldable meansin response to the vibrations of said strings and member to vary thefield of the electro-magnetic poles, and means for connecting saiddevice to a vibration transforming and amplifying mechanism.

2. In a stringed instrument, a solid body of bar form, a plurality ofstrings tensioned across portions of the body, a vibration transmittingdevice carried by the body, said device including a structure forsupporting portions of the tensioned strings, said structure having aresilient mounting supporting it directly upon said body portion andincluding armature portions straddling the body, an electro-magneticdevice carried by the body and arranged adjacent the armature portionswhereby vibrations of the strings are transmitted through said structureto the magnetic field and the magnetic field is varied by the vibrationof the armature therein, and means for connecting said device to avibration transforming and amplifying mechanism.

3. In a stringed instrument, a solid body of bar form, an armaturehaving a resilient mounting supporting it directly upon the body, abridge having its base portions seated directly upon the armature forsupport thereon, a plurality of strings tensioned across said bridgefrom one portion of the body to another, said armature having anextension arm, an electro-magnetic device carried by the body and havingportions arranged adjacent the extension arm of the armature to providefor vibration of said arm in the magnetic field of said device wherebyvibrations of the strings are transmitted into electric pulsatingcurrent of the same wave form as the wave form of the vibrations of thestrings.

4. In a stringed musical instrument, a solid body of bar form, armaturestructure having resilient mounting supporting it upon the body, abridge having its base portion seated upon the armature structure forsupport thereon, a plurality of strings tensioned across said bridge andfrom one portion of the body to another, a cup-like structure dependingfrom the armature and having metallic conductors coiled thereon toprovide portions of an electro-magnetic device, and a permanent magnethaving a portion extending into the cup-like structure; said armsturebeing responsive to vibrations of the strings to vibrate said cup-likestructure about the portion of the magnet disposed therein and therebyto vary the magnetic field of the electro-magnetic device.

5. In a stringed musical instrument, a solid body of bar form, armaturestructure having resilient mounting supporting it upon the body,

- a bridge having its base portions seated upon the armature structurefor support thereon, a plurality of strings tensioned across said bridgeand from one portion of the body to another, a cuplike deviceincorporated in said armature structure and having a low impedance coildisposed thereon to provide elements of an electro-magnetic mechanism, apermanent magnet having a portion extending into the cup-like device,said armature structure being responsive to vibrations of the strings tovibrate said cup-like device about portions of the magnet therein tovary the magnetic field of the electro-magnetic mechanism, and meansconnected to said low impedance coil for transforming and amplifyingvibrations transmitted to the electro-magnetic mechanism.

6. In a stringed instrument, a solid body of bar form, a stringtensioned across a portion of the body, a vibration transmitting devicecarried by the body of the instrument; said transmitting deviceincluding an oscillatory string contacting member for supporting aportion of the tensioned string, an electrically influenced magneticmechanism having poles providing a magnetic field, resilient meanscarried directly upon said body, armature structure incorporated withsaid member and confined directly between said resilient means and saidstring contacting member against vibration other than that transmitteddirectly from the string and string contacting member thereto, coactingparts of said armature structure and member extending at least toopposite edges of the body of the instrument, said armature structurehaving portions disposed in the magnetic field of said mechanism andbeing vibratory in response to the vibration of the string to vary theheld of said magnetic mechanism.

VICTOR A. PF'EIL.

